Method for substrate processing using exhaust ports

ABSTRACT

A substrate processing method in which processes with respect to substrates are performed comprises: stacking the substrates on a substrate holder disposed in a staking space formed within a lower chamber through a passage formed in a side of the lower chamber, exhausting the stacking space through an auxiliary exhaust port connected to the stacking space, moving the substrate holder into an external reaction tube closing an opened upper side of the lower chamber to provide a process space in which the processes are performed, and supplying a reaction gas into the process space using a supply nozzle connected to the process space and exhausting the process space using an exhaust nozzle connected to the process space and an exhaust port connected to the exhaust nozzle.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of co-pending U.S.application Ser. No. 14/357,592, filed on May 12, 2014, the disclosureof which is incorporated herein by reference. This application claimsbenefits under 35 U.S.C. § 1.119 to Korean Patent Application No.10-2011-0120257, filed on Nov. 17, 2011.

BACKGROUND OF THE INVENTION

The present invention disclosed herein relates to an apparatus andmethod for processing a substrate, and more particularly, to a substrateprocessing apparatus including exhaust ports and a substrate processingmethod.

Ordinary selective epitaxy processes involve deposition reaction andetching reaction. The deposition and etching reactions may occursimultaneously at slightly different reaction rates with respect to apolycrystalline layer and an epitaxial layer. While an existingpolycrystalline layer and/or an amorphous layer are/is deposited on atleast one second layer during the deposition process, the epitaxiallayer is formed on a surface of a single crystal. However, the depositedpolycrystalline layer is etched faster than the epitaxial layer. Thus,corrosive gas may be changed in concentration to perform a net selectiveprocess, thereby realizing the deposition of an epitaxial material andthe deposition of a limited or unlimited polycrystalline material. Forexample, a selective epitaxy process may be performed to form anepitaxial layer formed of a material containing silicon on a surface ofsingle crystal silicon without leaving the deposits on a spacer.

Generally, the selective epitaxy process has several limitations. Tomaintain selectivity during the selective epitaxy process, a chemicalconcentration and reaction temperature of a precursor should be adjustedand controlled over the deposition process. If an insufficient siliconprecursor is supplied, the etching reaction is activated to decrease thewhole process rate. Also, features of the substrate may be deterioratedwith respect to the etching. If an insufficient corrosive solutionprecursor is supplied, selectivity for forming the single crystallineand polycrystalline materials over the surface of the substrate may bereduced in the deposition reaction. Also, typical selective epitaxyprocesses are performed at a high reaction temperature of about 800° C.,about 1,000° C., or more. Here, the high temperature is unsuited for themanufacturing process due to uncontrolled nitridation reaction andthermal budge on the surface of the substrate.

SUMMARY OF THE INVENTION

The present invention provides a substrate processing apparatus andmethod which effectively exhaust the insides of stacking and exhaustspaces.

The present invention also provides a substrate processing apparatus andmethod which prevents a reaction gas from being deposited within a lowerchamber.

Further another object of the present invention will become evident withreference to following detailed descriptions and accompanying drawings.

Embodiments of the present invention provide substrate processingapparatuses in which processes with respect to substrates are performed,the substrate processing apparatuses including: a lower chamber havingan opened upper side, the lower chamber including a passage allowing thesubstrates to pass therethrough in a side thereof; an external reactiontube closing the opened upper side of the lower chamber to provide aprocess space in which the processes are performed; a substrate holderon which the one or more substrates are vertically stacked, thesubstrate holder being movable between a stacking position in which thesubstrates are stacked within the substrate holder and a processposition in which the processes with respect to the substrates areperformed; at least one supply nozzle disposed along an inner wall ofthe external reaction tube, the at least one supply nozzle having asupply hole for discharging a reaction gas; at least one exhaust nozzledisposed along the inner wall of the external reaction tube, the atleast one exhaust nozzle having an exhaust hole for suctioning annon-reaction gas and byproducts within the process space; and a rearexhaust line connected to the exhaust nozzle to discharge thenon-reaction gas and the byproducts which are suctioned through theexhaust hole, wherein the lower chamber includes an exhaust portconnecting the exhaust nozzle to the rear exhaust line and an auxiliaryexhaust port connecting a stacking space defined within the lowerchamber to the rear exhaust line.

In some embodiments, the substrate holder may be disposed within thestacking space at the stacking position and disposed within the processspace at the process position.

In other embodiments, the substrate processing apparatuses may furtherinclude an auxiliary exhaust line connected to the auxiliary exhaustport and a first auxiliary valve for opening or closing the auxiliaryexhaust line, wherein the first auxiliary exhaust valve may open theauxiliary exhaust line before the processes are performed to exhaust theinside of the stacking space.

In still other embodiments, the substrate processing apparatuses mayfurther include: an auxiliary exhaust line connected to the auxiliaryexhaust port; a first auxiliary exhaust valve opening or closing theauxiliary exhaust line; a front exhaust line connecting the exhaust portto the rear exhaust line; a pump disposed on the front exhaust line topump the inside of the front exhaust line; a main exhaust valve disposedon the front exhaust line to open or close the front exhaust line; asecond auxiliary exhaust valve disposed on a rear side of the firstauxiliary exhaust valve to open or close the auxiliary exhaust line; aconnection line connecting the auxiliary exhaust line to the frontexhaust line, the connection line having one end connected between thefirst auxiliary exhaust valve and the second auxiliary exhaust valve andthe other end connected to a front portion of the pump; and a connectionvalve disposed on the connection line to open or close the connectionline, wherein, before the processes are performed, the first auxiliaryexhaust valve, the connection valve, and the main exhaust valve are inopened states, and the second auxiliary exhaust valve may be in a closedstate.

In even other embodiments, the substrate processing apparatuses mayfurther include: an auxiliary exhaust line connected to the auxiliaryexhaust port; a first auxiliary exhaust valve opening or closing theauxiliary exhaust line; a front exhaust line connecting the exhaust portto the rear exhaust line; a pump disposed on the front exhaust line topump the inside of the front exhaust line; a main exhaust valve disposedon the front exhaust line to open or close the front exhaust line; asecond auxiliary exhaust valve disposed on a rear side of the firstauxiliary exhaust valve to open or close the auxiliary exhaust line; aconnection line connecting the auxiliary exhaust line to the frontexhaust line, the connection line having one end connected between thefirst auxiliary exhaust valve and the second auxiliary exhaust valve andthe other end connected to a front portion of the pump; and a connectionvalve disposed on the connection line to open or close the connectionline, wherein, before the processes are performed, the first and secondauxiliary exhaust valves and the main exhaust valve are in openedstates, and the connection valve may be in a closed state.

In yet other embodiments, the stacking space may have a pressure greaterthan that of the process space.

In other embodiments of the present invention, substrate processingmethods in which processes with respect to substrates are performedinclude: stacking the substrates on a substrate holder disposed in astaking space formed within a lower chamber through a passage formed ina side of the lower chamber; exhausting the stacking space through anauxiliary exhaust port connected to the stacking space; moving thesubstrate holder into an external reaction tube closing an opened upperside of the lower chamber to provide a process space in which theprocesses are performed; and supplying a reaction gas into the processspace using a supply nozzle connected to the process space andexhausting the process space using an exhaust nozzle connected to theprocess space and an exhaust port connected to the exhaust nozzle.

In some embodiments, the lower chamber may include the exhaust port andthe auxiliary exhaust port.

In other embodiments, substrate processing methods may further includeexhausting the stacking space through the auxiliary exhaust port whilethe reaction gas is supplied into the process space.

In still other embodiments, the stacking space may have a pressuregreater than that of the process space.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the present invention, and are incorporated in andconstitute a part of this specification. The drawings illustrateexemplary embodiments of the present invention and, together with thedescription, serve to explain principles of the present invention. Inthe drawings:

FIG. 1 is a schematic view of a semiconductor manufacturing equipmentaccording to an embodiment of the present invention;

FIG. 2 is a view of a substrate processed according to an embodiment ofthe present invention;

FIG. 3 is a flowchart illustrating a process for forming an epitaxiallayer according to an embodiment of the present invention;

FIG. 4 is a schematic view illustrating an epitaxial apparatus of FIG.1;

FIG. 5 is a cross-sectional view illustrating a lower chamber and asubstrate holder of FIG. 1;

FIG. 6 is a schematic cross-sectional view illustrating an externalreaction tube, an internal reaction tube, supply nozzles, and exhaustnozzles of FIG. 1;

FIG. 7 is a cross-sectional view illustrating arrangements of the supplynozzles and thermocouples of FIG. 1;

FIG. 8 is a cross-sectional view illustrating arrangements of theexhaust nozzles and the thermocouples of FIG. 1;

FIG. 9 is a view of supply lines respectively connected to supplynozzles of FIG. 1;

FIG. 10 is a view illustrating a flow of a reaction gas within theinternal reaction tube of FIG. 1;

FIGS. 11 to 13 are views illustrating an exhaust process using anexhaust port and an auxiliary exhaust port; and

FIG. 14 is a view illustrating a state in which the substrate holder ofFIG. 1 is moved into a process position.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Hereinafter, exemplary embodiments of the present invention will bedescribed in detail with reference to FIGS. 1 to 14. The presentinvention may, however, be embodied in different forms and should not beconstructed as limited to the embodiments set forth herein. Rather,these embodiments are provided so that this disclosure will be thoroughand complete, and will fully convey the scope of the present inventionto those skilled in the art. In the drawings, the shapes of componentsare exaggerated for clarity of illustration.

FIG. 1 is a schematic view of a semiconductor manufacturing equipment 1according to an embodiment of the present invention. The semiconductormanufacturing equipment 1 includes process equipment 2, an equipmentfront end module (EFEM) 3, and an interface wall 4. The EFEM 3 ismounted on a front side of the process equipment 2 to transfer a wafer Wbetween a container (not shown) in which substrates S are received andthe process equipment 2.

The EFEM 3 includes a plurality of loadports 60 and a frame 50. Theframe 50 is disposed between the loadports 60 and the process equipment2. The container in which the substrate S is received is placed on theloadports by a transfer unit (not shown) such as an overhead transfer,an overhead conveyor, or an automatic guided vehicle.

An airtight container such as a front open unified pod (FOUP) may beused as the container. A frame robot 70 for transferring the substrate Sbetween the container placed on the loadports 60 and the processequipment 2 is disposed within the frame 50. A door opener (not shown)for automatically opening or closing a door of the container may bedisposed within the frame 50. Also, a fan filter unit (FFU) (not shown)for supplying clean air into the frame 50 may be provided within theframe 50 so that the clean air flows downward from an upper side withinthe frame 50.

Predetermined processes with respect to the substrate S are performedwithin the process equipment 2. The process equipment 2 includes atransfer chamber 102, a loadlock chamber 106, cleaning chambers 108 aand 108 b, a buffer chamber 110, and epitaxial chambers (or epitaxialapparatuses) 112 a, 112 b, and 112 c. The transfer chamber 102 may havea substantially polygonal shape when viewed from an upper side. Theloadlock chamber 106, the cleaning chambers 108 a and 108 b, the bufferchamber 110, and the epitaxial chambers 112 a, 112 b, and 112 c aredisposed on a side surface of the transfer chamber 102.

The loadlock chamber 106 is disposed on a side surface adjacent to theEFEM 3 among side surfaces of the transfer chamber 102. The substrate Sis loaded to the process equipment 2 after the substrate S istemporarily stayed within the loadlock chamber 106 so as to perform theprocesses. After the processes are completed, the substrate S isunloaded from the process equipment 2 and then is temporarily stayedwithin the loadlock chamber 106. The transfer chamber 102, the cleaningchambers 108 a and 108 b, the buffer chamber 110, and the epitaxialchambers 112 a, 112 b, and 112 c are maintained in a vacuum state. Theloadlock chamber 106 is switched from the vacuum state into anatmospheric state. The loadlock chamber 106 prevents externalcontaminants from being introduced into the transfer chamber 102, thecleaning chambers 108 a and 108 b, the buffer chamber 110, and theepitaxial chambers 112 a, 112 b, and 112 c. Also, since the substrate Sis not exposed to the atmosphere during the transfer of the substrate S,it may prevent an oxide layer from being grown on the substrate S.

Gate valves (not shown) are disposed between the loadlock chamber 106and the transfer chamber 102 and between the loadlock chamber 106 andthe EFEM 3. When the substrate S is transferred between the EFEM 3 andthe loadlock chamber 106, the gate valve disposed between the loadlockchamber 106 and the transfer chamber 102 is closed. Also, when thesubstrate S is transferred between the loadlock chamber 106 and thetransfer chamber 102, the gate valve disposed between the loadlockchamber 106 and the EFEM 3 is closed.

A substrate handler 104 is disposed in the transfer chamber 102. Thesubstrate handler 104 transfers the substrate S between the loadlockchamber 106, the cleaning chamber 108 a and 108 b, the buffer chamber110, and the epitaxial chambers 112 a, 112 b, and 112 c. The transferchamber 102 is sealed so that the transfer chamber 102 is maintained inthe vacuum state when the substrate S is transferred. The maintenance ofthe vacuum state is for preventing the substrate S from being exposed tocontaminants (e.g., 02, particle materials, and the like).

The epitaxial chambers 112 a, 112 b, and 112 c are provided to form anepitaxial layer on the substrate S. In the current embodiment, threeepitaxial chambers 112 a, 112 b, and 112 c are provided. Since it takesa relatively long time to perform an epitaxial process when compared tothat of a cleaning process, manufacturing yield may be improved throughthe plurality of epitaxial chambers. Unlike the current embodiment, fouror more epitaxial chambers or two or less epitaxial chambers may beprovided.

The cleaning chambers 108 a and 108 b are configured to clean thesubstrate S before the epitaxial process is performed on the substrate Swithin the epitaxial chambers 112 a, 112 b, and 112 c. To successfullyperform the epitaxial process, an amount of oxide remaining on thecrystalline substrate should be minimized. If an oxygen content on asurface of the substrate S is too high, oxygen atoms may interruptcrystallographic disposition of materials to be deposited on a seedsubstrate, and thus, it may have a bad influence on the epitaxialprocess. For example, when a silicon epitaxial deposition is performed,excessive oxygen on the crystalline substrate may displace a siliconatom from its epitaxial position by oxygen atom clusters in atom units.The local atom displacement may cause errors in follow-up atomarrangement when a layer is more thickly grown. This phenomenon may beso-called stacking faults or hillock defects. Oxygenation on the surfaceof the substrate may, for example, occur when the substrate is exposedto the atmosphere while the substrate is transferred. Thus, the cleaningprocess for removing a native oxide (or a surface oxide) formed on thesubstrate S may be performed within the cleaning chambers 108 a and 108b.

The cleaning process may be a dry etching process using hydrogen (H*)and NF₃ gases having a radical state. For example, when the siliconoxide formed on the surface of the substrate is etched, the substrate isdisposed within a chamber, and then, the chamber has a vacuum atmospheretherein to generate an intermediate product reacting with the siliconoxide within the chamber.

For example, when reaction gases such as a hydrogen radical gas (H*) anda fluoride gas (for example, nitrogen fluoride (NF₃)) are supplied intothe chamber, the reaction gases are reduced as expressed in thefollowing reaction formula (1) to generate an intermediate product suchas NH_(x)F_(y) (where x and y are certain integers).H*+NF₃

NH_(x)F_(y)  (1)

Since the intermediate product has high reactivity with silicon oxide(SiO₂), when the intermediate product reaches a surface of the siliconsubstrate, the intermediate product selectively reacts with the siliconoxide to generate a reaction product ((NH₄)₂SiF₆) as expressed infollowing reaction formula (2).NH_(x)F_(y)+SiO₂

(NH₄)₂SiF₆+H₂O  (2)

Thereafter, when the silicon substrate is heated at a temperature ofabout 100° C. or more, the reaction product is pyrolyzed as expressed infollowing reaction formula (3) to form a pyrolyzed gas, and then, thepyrolyzed gas is evaporated. As a result, the silicon oxide may beremoved from the surface of the substrate. As shown in the followingreaction formula (3), the pyrolysis gas includes a gas containingfluorine such as an HF gas or a SiF₄ gas.(NH₄)₂SiF₆

NH₃+HF+SiF₄  (3)

As described above, the cleaning process may include a reaction processfor generating the reaction product and a heating process for pyrolyzingthe reaction product. The reaction process and the heating process maybe performed at the same time within the cleaning chambers 108 a and 108b. Alternatively, the reaction process may be performed within one ofthe cleaning chambers 108 a and 108 b, and the heating process may beperformed within the other one of the cleaning chambers 108 a and 108 b.

The buffer chamber 110 provides a space in which the substrate S, onwhich the cleaning process is completed, is stacked and a space in whichthe substrate S, on which the epitaxial process is performed, isstacked. When the cleaning process is completed, the substrate S istransferred into the buffer chamber 110 and then stacked within thebuffer chamber 110 before the substrate S is transferred into theepitaxial chambers 112 a, 112 b, and 112 c. The epitaxial chambers 112a, 112 b, and 112 c may be batch type chambers in which a single processis performed on a plurality of substrates. When the epitaxial process iscompleted within the epitaxial chambers 112 a, 112 b, and 112 c,substrates S on which the epitaxial process is performed aresuccessively stacked within the buffer chamber 110. Also, substrates Son which the cleaning process is completed are successively stackedwithin the epitaxial chambers 112 a, 112 b, and 112 c. Here, thesubstrates S may be vertically stacked within the buffer chamber 110.

FIG. 2 is a view of a substrate processed according to an embodiment ofthe present invention. As described above, the cleaning process isperformed on the substrate S within the cleaning chambers 108 a and 108b before the epitaxial process is performed on the substrate S. Thus, anoxide 72 formed on a surface of a substrate 70 may be removed throughthe cleaning process. The oxide may be removed through the cleaningprocess within the cleaning chamber 108 a and 108 b. Also, an epitaxysurface 74 formed on the surface of the substrate 70 may be exposedthrough the cleaning process to assist the growth of an epitaxial layer.

Thereafter, an epitaxial process is performed on the substrate 70 withinthe epitaxial chambers 112 a, 112 b, and 112 c. The epitaxial processmay be performed by chemical vapor deposition. The epitaxial process maybe performed to form an epitaxy layer 76 on the epitaxy surface 74. Theepitaxy surface 74 formed on the substrate 70 may be exposed by reactiongases including a silicon gas (e.g., SiCl₄, SiHCl₃, SiH₂Cl₂, SiH₃Cl,Si₂H₆, or SiH₄) and a carrier gas (e.g., N₂ and/or H₂). Also, when theepitaxy layer 76 is required to include a dopant, a silicon-containinggas may include a dopant-containing gas (e.g., AsH₃, PH₃, and/or B₂H₆),

FIG. 3 is a flowchart illustrating a process for forming an epitaxiallayer according to an embodiment of the present invention. In operationS10, a process for forming an epitaxial layer starts. In operation S20,a substrate S is transferred into cleaning chambers 108 a and 108 bbefore an epitaxial process is performed on the substrate S. Here, asubstrate handler 104 transfers the substrate S into the cleaningchambers 108 a and 108 b. The substrate S is transferred through atransfer chamber 102 in which a vacuum state is maintained. In operationS30, a cleaning process is performed on the substrate S. As describedabove, the cleaning process includes a reaction process for generating areaction product and a heating process for pyrolyzing the reactionproduct. The reaction process and the heating process may be performedat the same time within the cleaning chambers 108 a and 108 b.Alternatively, the reaction process may be performed within one of thecleaning chambers 108 a and 108 b, and the heating process may beperformed within the other one of the cleaning chambers 108 a and 108 b.

In operation S40, the substrate S on which the cleaning process iscompleted is transferred into a buffer chamber 110 and is stacked withinthe buffer chamber 110. Then, the substrate S is on standby within thebuffer chamber 110 so as to perform the epitaxial process. In operationS50, the substrate S is transferred into epitaxial chambers 112 a, 112b, and 112 c. The transfer of the substrate S is performed through thetransfer chamber 102 in which the vacuum state is maintained. Inoperation S60, an epitaxial layer may be formed on the substrate S. Inoperation S70, the substrate S is transferred again into the bufferchamber 110 and is stacked within the buffer chamber 110. Thereafter, inoperation S80, the process for forming the epitaxial layer is ended.

FIG. 4 is a schematic view illustrating an epitaxial apparatus ofFIG. 1. FIG. 5 is a cross-sectional view illustrating a lower chamberand a substrate holder of FIG. 1. An epitaxial apparatus (or anepitaxial chamber) includes a lower chamber 312 b having an opened upperside. The lower chamber 312 b is connected to a transfer chamber 102.The lower chamber 312 b has a passage 319 connected to the transferchamber 102. A substrate S may be loaded from the transfer chamber 102into the lower chamber through the passage 319. A gate valve (not shown)may be disposed outside the passage 319. The passage 319 may be openedor closed by the gate valve.

The epitaxial apparatus includes a substrate holder 328 on which aplurality of substrates S are stacked. The substrates S are verticallystacked on the substrate holder 328. For example, fifteen substrates Smay be stacked on the substrate holder 328. When the substrate holder328 is disposed in a stacking space (or at a “stacking position)provided within the lower chamber 312 b, the substrates S may be stackedwithin the substrate holder 328. As described below, the substrateholder 328 may be elevated. When the substrates S are stacked into aslot of the substrate holder 328, the substrate holder 328 may beelevated so that substrates S are stacked into the next slot of thesubstrate holder 328. When all the substrates are stacked on thesubstrate holder 328, the substrate holder 328 is moved into an externalreaction tube 312 a (or to a “process position”), an epitaxial processis performed within the external reaction tube 312 a.

A heat-shield plate 316 is disposed under the substrate holder 328 andelevated together with the substrate holder 328. When the substrateholder 328 is moved in position to the process position, as shown inFIG. 14, the heat-shield plate 316 closes an opened lower portion of theinternal reaction tube 314. The heat-shield plate 316 may be formed ofceramic, quartz, or a metal material coated with ceramic. Theheat-shield plate 316 prevents heat within a reaction region from beingtransmitted into the stacking space when processes are performed. Aportion of a reaction gas supplied into the reaction region may be movedinto the stacking space through the opened lower side of the internalreaction tube 314. Here, when the stacking space has a temperaturegreater than a predetermined temperature, a portion of the reaction gasmay be deposited on an inner wall of the stacking space. Thus, it may benecessary to prevent the stacking space from being heated due to theheat-shield plate 316. Therefore, it may prevent the reaction gas frombeing deposited on the inner wall of the stacking space.

A lower chamber 312 b includes an exhaust port 344, an auxiliary exhaustport 328 a, and an auxiliary gas supply port 362. The exhaust port 344has a “

” shape. An exhaust nozzle unit 334 that will be described later areconnected to a first exhaust line 342 through the exhaust port 344. Theauxiliary exhaust port 328 a is connected to the auxiliary exhaust line328 b. A gas within the stacking space of the lower chamber 312 b may beexhausted the auxiliary exhaust port 328 a.

The auxiliary gas supply port 362 is connected to a auxiliary gas supplyline (not shown) to supply a gas supplied through the auxiliary gassupply line into the stacking space. For example, an inert gas may besupplied into the stacking space through the auxiliary gas supply port362. As the inert gas is supplied into the stacking space, it mayprevent the reaction gas supplied into the process space from beingintroduced into the stacking space.

Furthermore, since the inert gas is continuously supplied into thestacking space and exhausted through the auxiliary exhaust port 328 a,it may prevent the reaction gas supplied into the process space frombeing moved into the stacking space. Here, the stacking space may be setso that an internal pressure thereof is slightly greater than that ofthe process space. When the stacking pace has a pressure slightlygreater than that of the process space, the reaction gas within theprocess space is not moved into the stacking space.

FIG. 6 is a schematic cross-sectional view illustrating the externalreaction tube, the internal reaction tube, supply nozzles, and theexhaust nozzles of FIG. 1. The external reaction tube 312 a closes anopened upper side of the lower chamber 312 b to provide the processspace in which the epitaxial process is performed. A support flange 442is disposed between the lower chamber 312 b and the external reactiontube 312 a. The external reaction tube 312 is disposed on the supportflange 442. The stacking space of the lower chamber 312 b communicateswith the process space of the external reaction tube 312 a through anopening defined in a center of the support flange 442. As describedabove, when all the substrates are stacked on the substrate holder 328,the substrate holder 328 may be moved into the process space of theexternal reaction tube 312 a.

The internal reaction tube 314 is disposed inside the external reactiontube 312 a to provide a reaction region with respect to a substrate S.The inside of the external reaction tube 312 a is divided into areaction region and a non-reaction region by the internal reaction tube314. The reaction region is defined inside the internal reaction tube314, and the non-reaction region is defined outside the internalreaction tube 314. When the substrate holder 328 is moved to the processposition, the substrate holder 328 is disposed in the reaction region.The reaction region has a volume less than that of the process space.Thus, when the reaction gas is supplied into the reaction region, ausage amount of the reaction gas may be minimized. Also, the reactiongas may be concentrated onto the substrates S stacked within thesubstrate holder 328. The internal reaction tube 314 has a closed upperside and an opened lower side. Thus, the substrate holder 328 is movedinto the reaction region through the lower side of the internal reactiontube 314.

As shown in FIG. 4, a side heater 324 and an upper heater 326 aredisposed to surround the external reaction tube 312 a. The side heater324 and the upper heater 326 heat the process space within the externalreaction tube 312 a. Thus, the reaction space (or the reaction region)may reach a temperature enough to perform the epitaxial process. Theside heater 324 and the upper heater 326 are connected to an upperelevation rod 337 through a support frame 327. When the upper elevationrod 337 is rotated by an elevation motor 338, the support frame 327 maybe elevated.

The epitaxial apparatus further includes a gas supply unit. The gassupply unit includes a supply nozzle unit 332 and an exhaust nozzle unit334. The supply nozzle unit 332 includes a plurality of supply tubes 332a and a plurality of supply nozzles 332 b. The supply nozzles 332 b areconnected to the supply tubes 332 a, respectively. Each of the supplynozzles 332 b has a circular tube shape. A supply hole 332 c is definedin a front end of each of the supply nozzles 332 b. The reaction gas isdischarged through the supply hole 332 c. The supply hole 332 c has acircular sectional area. As shown in FIG. 6, the supply holes 332 c ofthe supply nozzles 332 b may be defined at heights different from eachother.

The supply tubes 332 a and the supply nozzles 332 b are disposed insidethe external reaction tube 312 a. The supply tubes 332 a extendvertically. The supply nozzles 332 b may be disposed substantiallyperpendicular to the supply tubes 332 a. The supply holes 332 c aredefined inside the internal reaction tube 314. Thus, the reaction gasdischarged through the supply holes 332 c may be concentrated into thereaction region within the internal reaction tube 314. The internalreaction tube 314 has a plurality of through-holes 374. The supply holes332 c of the supply nozzles 332 b may be defined inside the internalreaction tube 314 through the through-holes 374.

FIG. 7 is a cross-sectional view illustrating arrangements of the supplynozzles and thermocouples of FIG. 1. Referring to FIG. 7, the supplynozzles 332 b have circular supply holes 332 c, respectively. The supplyholes 332 c of the supply nozzles 332 b are defined in a circumferencedirection along an inner wall of the internal reaction tube 314. Also,the supply holes 332 c are defined in heights different from each other.When the substrate holder 328 is moved into the process position, thesupply nozzles 332 b spray the reaction gas onto each of the substratesS placed on the substrate holder 328. Here, the supply holes 332 c aredisposed at height substantially equal to those of the substrates S,respectively. As shown in FIG. 6, the supply nozzles 332 b are connectedto reaction gas sources (not shown) through the supply lines 372disposed in the support flange 442, respectively.

Each of reaction gas sources may supply a deposition gas (a silicon gas(e.g., SiCl₄, SiHCl₃, SiH₂Cl₂, SiH₃Cl, Si₂H₆, or SiH₄)), a carrier gas(e.g., N₂ and/or H₂), or an etching gas. A selective epitaxy processinvolves deposition reaction and etching reaction. Although not shown inthe current embodiment, when an epitaxy layer is required to include adopant, a dopant-containing gas (e.g., arsine (AsH₃), phosphine (PH₃),and/or diborane (B₂H₆)) may be supplied. Also, in case of a cleaning oretching process, hydrogen chloride (HCl) may be supplied.

As shown in FIG. 6, the exhaust nozzle unit 334 includes a plurality ofexhaust tubes 334 a and a plurality of exhaust nozzles 334 b. Theexhaust nozzles 334 b are connected to the exhaust tubes 334 a,respectively. An exhaust hole 334 c is defined in a front end of each ofthe exhaust nozzles 334 b to suction a non-reaction gas and byproducts.The exhaust hole 334 c has a sectional area having a slot shape. Asshown in FIG. 6, the exhaust nozzles 334 b may be disposed at heightsdifferent from those of the exhaust holes 334 c.

The exhaust tubes 334 a and the exhaust nozzles 334 b are disposedinside the external reaction tube 312 a. The exhaust tubes 334 a extendvertically. The exhaust nozzles 334 b may be disposed substantiallyperpendicular to the exhaust tubes 334 a. The exhaust holes 334 c aredefined inside the internal reaction tube 314. Thus, the non-reactiongas and byproducts may be effectively suctioned from the reaction regionwithin the internal reaction tube 314 through the exhaust holes 334 c.The internal reaction tube 314 has a plurality of through-holes 376. Theexhaust holes 334 c of the exhaust nozzles 334 b may be defined insidethe internal reaction tube 314 through the through-holes 376.

FIG. 8 is a cross-sectional view illustrating arrangements of theexhaust nozzles and the thermocouples of FIG. 1. Referring to FIG. 8,the exhaust nozzles 334 b have exhaust holes 334 c, each having aslot-shaped sectional area, respectively. The exhaust holes 334 c of theexhaust nozzles 334 b are defined in a circumference direction along theinner wall of the internal reaction tube 314. Also, the exhaust holes334 c are defined at heights different from each other. The substrateholder 328 is moved into the process position, the supply nozzles 332 bspray the reaction gas onto each of the substrates S placed on thesubstrate holder 328. Here, the non-reaction gas and byproducts may begenerated within the internal reaction tube 314. The exhaust nozzles 334b suction the non-reaction gas and the byproducts to discharge thenon-reaction gas and the byproducts to the outside. The exhaust holes334 c are defined at heights substantially equal to those of thesubstrates S, respectively. As shown in FIG. 4, the exhaust nozzles 334b are connected to the first exhaust line 342 through the exhaust port344 disposed in the lower chamber 312 b to discharge the non-reactiongas and the byproducts through the first exhaust line 342. The switchingvalve 346 is disposed on the first exhaust line 342 to open or close thefirst exhaust line 342. The turbo pump 348 is disposed on the firstexhaust line 342 to forcibly discharge the non-reaction gas and thebyproducts through the first exhaust line 342. The first exhaust line342 is connected to the second exhaust line 352 to discharge thenon-reaction gas and the byproducts, which are moved along the firstexhaust line 342, through the second exhaust line 352.

The auxiliary exhaust port 328 a is disposed in the lower chamber 312 b.The auxiliary exhaust line 328 b is connected to the auxiliary exhaustport 328 a. The auxiliary exhaust line 328 b is connected to the secondexhaust line 352. The first and second auxiliary valves 328 c and 328 dare disposed on the auxiliary exhaust line 328 b to open or close theauxiliary exhaust line 328 b. The auxiliary exhaust line 328 b isconnected to the first exhaust line 342 through a connection line 343. Aconnection valve 343 a is disposed on the connection line 343 to open orclose the connection line 343.

As shown in FIGS. 7 and 8, thermocouples 382 and 384 are disposedbetween the external reaction tube 312 a and the internal reaction tube314. The thermocouples 382 and 384 are vertically disposed to measuretemperatures according to heights. Thus, a worker may grasp temperatureswithin the process space according to the heights. As a result, effectsof temperature distribution on the process may be previously checked.

FIG. 9 is a view of supply lines 372 respectively connected to supplynozzles of FIG. 1. As shown in FIG. 9, the supply nozzles 332 areconnected to the reaction gas sources (not shown) through the supplylines 372. Thus, the reaction gas may be uniformly supplied into thereaction region of the internal reaction tube 314 through the pluralityof supply nozzles 332. If one of the supply lines 372 is connected to aplurality of supply nozzles 332, the reaction gas may be supplied withdifferent flow rates according to the supply nozzles 332. Thus, aprocess rate may vary according to the positions of the substrate holder328.

FIG. 10 is a view illustrating a flow of a reaction gas within theinternal reaction tube of FIG. 1. As described above, the supply holes332 c of the supply nozzles 332 b are defined in the circumferencedirection along the inner wall of the internal reaction tube 314. Also,the supply holes 332 c are defined at height different from each other.Also, the exhaust holes 334 c of the exhaust nozzles 334 b are definedin the circumference direction along the inner wall of the internalreaction tube 314. Also, the exhaust holes 334 c are defined at heightsdifferent from each other. Here, a center of each of the supply holes332 c is symmetric to that of each of the exhaust holes 334 c withrespect to the same height. That is, the supply hole 332 c of the supplynozzle 332 b and the exhaust hole 334 c of the exhaust nozzle 334 b aredisposed opposite to each other with respect to a center of thesubstrate S stacked on the substrate holder 328. Thus, the reaction gassprayed from the supply nozzle 332 b flows toward the exhaust nozzle 334b disposed opposite to the supply nozzle 332 b (indicated as an arrow).Thus, it may secure a sufficient time for which the reaction gas and thesubstrate S react with each other. Here, the non-reaction gas and thebyproducts generated during the process are suctioned and dischargedthrough the exhaust nozzle 334 b.

As shown in FIG. 10, a flow of the reaction gas may vary according to aheight of the substrates S stacked on the substrate holder 328. Thus,the flow of the reaction gas has a phase difference according to aheight of the substrate S. That is, a position of the supply hole 332 cof the supply nozzle 332 b and a position of the exhaust hole 334 c ofthe exhaust nozzle 334 b have a phase difference according to the heightof the substrate S. Referring to FIG. 10, a reference numeral {circlearound (1)} denotes a flow of a reaction gas flowing from the supplynozzle 332 b toward the exhaust nozzle 334 b, and a reference numeral{circle around (2)} denotes a flow of a reaction gas flowing from thesupply nozzle 332 b toward the exhaust nozzle 334 b. The referencenumerals {circle around (1)} and {circle around (2)} have a phasedifference of a predetermined angle. Thus, the reaction gas sprayed fromthe supply hole may be diffused by the reaction gas sprayed from thesupply hole defined at a different height. That is, the flows of thereaction gas having the phase difference may interfere with each other.Thus, the reaction gas may be moved toward the exhaust nozzle 334 b in astate where the reaction gas is diffused by the interference.

Also, the supply hole 332 c of the supply nozzle 332 b has a circularshape. On the other hand, the exhaust hole 334 c of the exhaust nozzle334 b has a slot shape. Thus, the reaction gas sprayed from the supplyhole 332 c of the supply nozzle 332 b may be diffused to have apredetermined width according to a shape of the exhaust hole 334 c (seeFIG. 10). Therefore, an area on which the reaction gas contacts asurface of the substrate S may be increased. Also, the sufficientreaction may be induced to restrict the generation of the non-reactiongas. The reaction gas laminar-flows on the substrate S from the supplyhole 332 c up to the exhaust hole 334 c.

FIGS. 11 to 13 are views illustrating an exhaust process using anexhaust port and an auxiliary exhaust port. As shown in FIG. 4, theexhaust nozzles 334 b are connected to the first exhaust line 342through the exhaust port 344 disposed in the lower chamber 312 b todischarge the non-reaction gas and the byproducts through the firstexhaust line 342. The switching valve 346 is disposed on the firstexhaust line 342 to open or close the first exhaust line 342. The turbopump 348 is disposed on the first exhaust line 342 to forcibly dischargethe non-reaction gas and the byproducts through the first exhaust line342. The first exhaust line 342 is connected to the second exhaust line352 to discharge the non-reaction gas and the byproducts, which aremoved along the first exhaust line 342, through the second exhaust line352.

The auxiliary exhaust port 328 a is disposed in the lower chamber 312 b.The auxiliary exhaust line 328 b is connected to the auxiliary exhaustport 328 a. The auxiliary exhaust line 328 b is connected to the secondexhaust line 352. The first and second auxiliary valves 328 c and 328 dare disposed on the auxiliary exhaust line 328 b to open or close theauxiliary exhaust line 328 b. The auxiliary exhaust line 328 b isconnected to the first exhaust line 342 through a connection line 343. Aconnection valve 343 a is disposed on the connection line 343 to open orclose the connection line 343.

The auxiliary exhaust port 328 a will be described in detail below.First, before a process is performed, the inside of the lower chamber312 b and the inside of the external reaction tube 312 a (or theinternal reaction tube 314) should be in vacuum state. Here, the workermay the inner vacuum states of the lower chamber 312 b and the externalreaction tube 312 a (or the internal reaction tube 314) using theauxiliary exhaust port 328 a. The worker may close the connection valve343 a and the switching valve 346 in a state where the first and secondauxiliary valves 328 c. In this case, a gas may be exhausted through theauxiliary exhaust line 328 b and the second exhaust line 352.

Next, when the gas and the byproducts are exhausted through theauxiliary exhaust line 328 b and the second exhaust line 352 for apredetermined time, the worker may close the second auxiliary valve 328d in a state where the first auxiliary valve 328 c, the connection valve343 a, and the switching valve 346. In this case, the exhaust processmay be performed through the auxiliary exhaust line 328 b, theconnection line 343, the first exhaust line 342, and the second exhaustline 352. Here, the exhaust process may be performed through the turbopump 348. The turbo pump 348 may change an inner pressure of each of thelower chamber 312 b and the external reaction tube 312 a (or theinternal reaction tube 314) into a process pressure using the turbo pump348.

When the insides of the lower chamber 312 b and the external reactiontube 312 a (or the internal reaction tube 314) become in the vacuumstate through above-described two stages, it may prevent an excessivepressure from being applied to the lower chamber 312 b and the externalreaction tube 312 a (or the internal reaction tube 314) due to thehigh-performance turbo pump 348. Also, in a case where the vacuum isformed using the auxiliary exhaust port 328 a directly connected to thelower chamber 312 b, the vacuum may be effectively formed when comparedto a case in which the vacuum is formed using the exhaust port 344connected to the exhaust nozzles 334.

During the process, the worker may close the connection valve 343 a in astate where the first and second auxiliary valves 328 c and 328 d andthe switching valve 346 are opened. In this case, the non-reaction gasand the byproducts suctioned through the exhaust nozzles 334 may bedischarged through the first and second exhaust lines 342 and 352. Also,the inert gas may be supplied into the stacking space of the lowerchamber 312 b through the auxiliary gas supply port 362. In addition,the inert gas within the stacking space of the lower chamber 312 b maybe discharged to the outside through the auxiliary exhaust line 328 b.The stacking space may be set to a pressure slightly greater than thatof the process space. Also, it may prevent the reaction gas within theprocess space from being moved into the stacking space.

As shown in FIG. 4, the substrate holder 328 is connected to therotation shaft 318. The rotation shaft 318 passes through the lowerchamber 312 b and is connected to an elevation motor 319 a and arotation motor 319 b. The rotation motor 319 b is disposed on s motorhousing 319 c. The rotation motor 319 b drives the rotation shaft 318while the epitaxial process is performed to rotate the substrate holder328 (and the substrates S) together with the rotation shaft 318. This isdone because the reaction gas flows from the supply hole 332 c towardthe exhaust hole 334 c, and the reaction gas is reduced in concentrationas the reaction gas is deposited on the substrate S from the supply hole332 c toward the exhaust hole 334 c. To prevent the above-describedphenomenon from occurring, the substrate S may be rotated so that thereaction gas is uniformly deposited on the surface of the substrate S.

The motor housing 319 c is fixed to a bracket 319 d. The bracket 319 dis connected to the elevation rod 319 e connected to a lower portion ofthe lower chamber 312 b and elevated along the elevation rod 319 e. Thebracket 319 c is screw-coupled to a lower rod 419, and the lower rod 419is rotated by the elevation motor 319 a. That is, the lower rod 419 isrotated as the elevation motor 319 a is rotated. Thus, the bracket 319 dand the motor housing 319 c may be elevated together. Therefore, therotation shaft 318 and the substrate holder 328 may be elevatedtogether. The substrate holder 328 may be moved from the stackingposition into the process position by the elevation motor 319 a. Abellows 318 a connects the lower chamber 312 b to the motor housing 319c. Thus, the inside of the lower chamber 312 b may be sealed. FIG. 11 isa view illustrating a state in which the substrate holder of FIG. 1 ismoved into a process position.

Referring to FIG. 11, the heat-shield plate 316 is disposed under thesubstrate holder 328. As the rotation shaft 318 is elevated, thesubstrate holder 328 is elevated together with the rotation shaft 318.The heat-shield plate 316 closes the opened lower side of the internalreaction tube 314 to prevent heat within the internal reaction tube 314from being transmitted into the stacking space within the lower chamber312 b.

According to the embodiment, the stacking space and the exhaust spacemay be effectively exhausted to prevent the reaction gas from beingdeposited within the lower chamber.

Although the present invention is described in detail with reference tothe exemplary embodiments, the invention may be embodied in manydifferent forms. Thus, technical idea and scope of claims set forthbelow are not limited to the preferred embodiments.

What is claimed is:
 1. A method for substrate processing, the methodcomprising: stacking the substrates on a substrate holder disposed in astacking space formed within a lower chamber through a passage formed ina side of the lower chamber; exhausting the stacking space through anauxiliary exhaust port connected to the stacking space, the auxiliaryexhaust port being formed in the lower chamber and being connected tothe stacking space; moving the substrate holder into an externalreaction tube closing an opened upper side of the lower chamber toprovide a process space in which the processes are performed; andsupplying a reaction gas into the process space using a supply nozzleconnected to the process space and exhausting the process space using anexhaust nozzle connected to the process space and an exhaust portconnected to the exhaust nozzle, the exhaust port being formed in thelower chamber and being connected to a first exhaust line that isconnected to a second exhaust line, wherein exhausting the stackingspace is performed by: setting a first auxiliary exhaust valve disposedon an auxiliary exhaust line in an opened state, the auxiliary exhaustline connected to the auxiliary exhaust port and the second exhaustline; setting a second auxiliary exhaust valve disposed on the auxiliaryexhaust line and disposed on a position located downstream of the firstauxiliary exhaust valve in a closed state; setting a connection valvedisposed on a connection line in an opened state, the connection lineconnecting the auxiliary exhaust line to the first exhaust line, theconnection line having one end connected to the auxiliary exhaust lineat a point between the first auxiliary exhaust valve and the secondauxiliary exhaust valve and the other end connected to the first exhaustline; and setting a main exhaust valve disposed on the first exhaustline in an opened state, wherein exhausting the process space using anexhaust nozzle is performed by: setting the first auxiliary exhaustvalve, the second auxiliary exhaust valve and the main exhaust valve inopened states; and setting the connection valve in a closed state. 2.The substrate processing method of claim 1, wherein the stacking spacehas a pressure greater than that of the process space.
 3. The substrateprocessing method of claim 1, further comprising: pre-exhausting thestacking space through the auxiliary exhaust port, whereinpre-exhausting the stacking space is performed by: setting the firstauxiliary exhaust valve and the second auxiliary exhaust valve in openedstates; setting the main exhaust valve and the connection valve inclosed states.